I've only gone through the harbor photos, but they are really quite good. I wonder how the print quality is; they're quite reasonably priced.
I've just been looking at a colleague's copy of the book that's advertised on the website and the reproduction is pretty good (A4 sized). I imagine the prints will be at least as good and, like you say, the prices aren't excessive.
The gallery was closed when we went past during our brief stay up there a couple of months ago - or I'd have gone in and checked it out. We're planning to go back sometime in 2017/8 for a bit longer stay and, hopefully, better weather.
If you're interested, there's a few snaps of modern-day Whitby on my website:
www.pauljenkin.com